How to Travel in the Sixteen Prefectures of Youyun (Part 1)

What are the Sixteen Prefectures of Youyun? The Sixteen Prefectures of Youyun is a historical and geographical concept, also known as the Sixteen Prefectures of Yanyun, referring to the sixteen prefectures and their territories around Youzhou and Yunzhou during the hundreds of years between the Tang and Yuan dynasties in Chinese history. After the Tang Dynasty was destroyed by Zhu Wen and replaced by the Later Liang, the Later Liang was replaced by the Later Tang of Li Cunxu. Shi Jingtang, the Jiedushi of Hedong in the Later Tang, borrowed troops from the Khitan (later known as Liao), a minority regime in the north, to destroy the Later Tang and establish the Later Jin at the cost of the Sixteen Prefectures of Youyun. Since then, the Sixteen Prefectures of Youyun, which had always been controlled by the Central Plains dynasty, fell into the hands of the northern nomads. Why the Sixteen Prefectures of Youyun? The Liao, Jin, and Yuan dynasties successively managed the Sixteen Prefectures of Youyun for more than 400 years, and it was not until the Ming Dynasty that this land was completely recovered by the Central Plains dynasty. Before the Five Dynasties and Ten Kingdoms period, the northern enemies faced by the Central Plains dynasty mainly came from the northwest; after that, the focus of the Central Plains dynasty shifted eastward, and the Yanshan and Taihang Mountains where the Sixteen Prefectures of Youyun were located, together with the passes of the Great Wall, became a barrier against the northern barbarians. Losing the Sixteen Prefectures of Youyun was equivalent to opening the door to the entire North China Plain, and even Guanzhong, the core of the Central Plains, with basically no natural barriers to defend. The Song Dynasty was called the "weak Song" not only because of its national policy of advocating literature and suppressing martial arts, but also because the Northern Song Dynasty did not control the Sixteen Prefectures of Youyun. Where are the Sixteen Prefectures of Youyun now? The two most important prefectures in the Sixteen Prefectures of Youyun are Youzhou and Yunzhou, the former roughly corresponding to the urban area of Beijing, and the latter referring to Datong. The other fourteen prefectures of the Sixteen Prefectures of Youyun are Shunzhou, Ruzhou, Tanzhou, Jizhou, Zhuozhou, Yingzhou, Mozhou, Xinzhou, Guizhou, Wuzhou, Weizhou, Yingzhou, Huanzhou, and Shuozhou. Historically, the Sixteen Prefectures of Youyun spanned the present-day Beijing-Tianjin and Shanxi-Hebei provinces, specifically including the northern districts and counties of Beijing and Tianjin, the southeastern part of Zhangjiakou in Hebei, the northeastern part of Datong, Shuozhou, and Xinzhou in Shanxi, and the intersection of Baoding, Langfang, and Cangzhou in Hebei.